Why can’t we refrain from sneezing?

To be discreet or to avoid spreading our germs everywhere … it often happens that we refrain from sneezing. That’s a very bad idea! This mania can have adverse effects on the body.


Who has never stopped sneezing so as not to disturb or scare the people around, especially in this time of the COVID-19 epidemic? It must be recognized that many of us have done it mechanically. But this reflex of the human body is not trivial, holding it back can have harmful effects.

A sneeze throws air at more than 50km / h

A sneeze is a natural phenomenon. This sudden expiration of air through the mouth and nose is caused by a convulsive movement of the expiratory muscles such as the diaphragm due to the presence of a disturbing or irritating element in the nasal mucous membranes.

In addition, sneezing revitalizes the mucus circulation system whose role is to trap and expel dust, pollen, or other foreign elements present in the respiratory system.

While sneezing is often caused by the presence of irritants in the nasal mucosa, other causes can be the source of many “tears”. Allergic people can have attacked if they are in the presence of the allergen (animal hair, pollen, etc.). The common cold, rhinitis, too strong a perfume, nasal polyposis can also cause them. Some patients also suffer from a photo-starting reflex. That is, they sneeze when exposed to strong light, or even sunlight! Between 18% and 35% of French people are affected by this syndrome.

A study from the University Hospital of Alberta in Canada, published in 2013, found that the air projected during a sneeze could be as fast as a scooter. Indeed, if the speed was on average about 4.5 m / s (or nearly 16 km / h), projections could reach up to 50 km / h under certain circumstances.

Micro-droplets that can travel up to 9 meters

When we sneeze, we expel a cloud of air and gas in which droplets of several sizes are suspended. According to the work of researchers from MIT (Massachusetts Institute of Technology, Boston), published in 2014 in the scientific journal Journal of Fluids Mechanics, it makes it possible for these potentially infectious “micropostillons” to remain in the air longer.

This mechanism allows the droplets to travel great distances. Experts have estimated that without the help of the cloud, those larger than 100 micrometers are able to travel 2 meters and the smallest less than one meter. With the cloud, the droplets can travel up to 6 meters

For scientists at the University of Alberta Hospital in Canada, sneezing is even more serious. They estimate that the bacteria and viruses present in the expelled droplets are able to travel up to 9 meters away.

Scientists disagree slightly on the length of the cloud. However, healthcare professionals agree on one point: refraining from sneezing is not recommended. Indeed, if this allows you to be more discreet, it is not without consequences on your body.

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